1 #ifndef _ALPHA_SPINLOCK_H
2 #define _ALPHA_SPINLOCK_H
3
4 #include <linux/kernel.h>
5 #include <asm/current.h>
6
7 /*
8 * Simple spin lock operations. There are two variants, one clears IRQ's
9 * on the local processor, one does not.
10 *
11 * We make no fairness assumptions. They have a cost.
12 */
13
14 #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
15 #define arch_spin_is_locked(x) ((x)->lock != 0)
16 #define arch_spin_unlock_wait(x) \
17 do { cpu_relax(); } while ((x)->lock)
18
arch_spin_value_unlocked(arch_spinlock_t lock)19 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
20 {
21 return lock.lock == 0;
22 }
23
arch_spin_unlock(arch_spinlock_t * lock)24 static inline void arch_spin_unlock(arch_spinlock_t * lock)
25 {
26 mb();
27 lock->lock = 0;
28 }
29
arch_spin_lock(arch_spinlock_t * lock)30 static inline void arch_spin_lock(arch_spinlock_t * lock)
31 {
32 long tmp;
33
34 __asm__ __volatile__(
35 "1: ldl_l %0,%1\n"
36 " bne %0,2f\n"
37 " lda %0,1\n"
38 " stl_c %0,%1\n"
39 " beq %0,2f\n"
40 " mb\n"
41 ".subsection 2\n"
42 "2: ldl %0,%1\n"
43 " bne %0,2b\n"
44 " br 1b\n"
45 ".previous"
46 : "=&r" (tmp), "=m" (lock->lock)
47 : "m"(lock->lock) : "memory");
48 }
49
arch_spin_trylock(arch_spinlock_t * lock)50 static inline int arch_spin_trylock(arch_spinlock_t *lock)
51 {
52 return !test_and_set_bit(0, &lock->lock);
53 }
54
55 /***********************************************************/
56
arch_read_can_lock(arch_rwlock_t * lock)57 static inline int arch_read_can_lock(arch_rwlock_t *lock)
58 {
59 return (lock->lock & 1) == 0;
60 }
61
arch_write_can_lock(arch_rwlock_t * lock)62 static inline int arch_write_can_lock(arch_rwlock_t *lock)
63 {
64 return lock->lock == 0;
65 }
66
arch_read_lock(arch_rwlock_t * lock)67 static inline void arch_read_lock(arch_rwlock_t *lock)
68 {
69 long regx;
70
71 __asm__ __volatile__(
72 "1: ldl_l %1,%0\n"
73 " blbs %1,6f\n"
74 " subl %1,2,%1\n"
75 " stl_c %1,%0\n"
76 " beq %1,6f\n"
77 " mb\n"
78 ".subsection 2\n"
79 "6: ldl %1,%0\n"
80 " blbs %1,6b\n"
81 " br 1b\n"
82 ".previous"
83 : "=m" (*lock), "=&r" (regx)
84 : "m" (*lock) : "memory");
85 }
86
arch_write_lock(arch_rwlock_t * lock)87 static inline void arch_write_lock(arch_rwlock_t *lock)
88 {
89 long regx;
90
91 __asm__ __volatile__(
92 "1: ldl_l %1,%0\n"
93 " bne %1,6f\n"
94 " lda %1,1\n"
95 " stl_c %1,%0\n"
96 " beq %1,6f\n"
97 " mb\n"
98 ".subsection 2\n"
99 "6: ldl %1,%0\n"
100 " bne %1,6b\n"
101 " br 1b\n"
102 ".previous"
103 : "=m" (*lock), "=&r" (regx)
104 : "m" (*lock) : "memory");
105 }
106
arch_read_trylock(arch_rwlock_t * lock)107 static inline int arch_read_trylock(arch_rwlock_t * lock)
108 {
109 long regx;
110 int success;
111
112 __asm__ __volatile__(
113 "1: ldl_l %1,%0\n"
114 " lda %2,0\n"
115 " blbs %1,2f\n"
116 " subl %1,2,%2\n"
117 " stl_c %2,%0\n"
118 " beq %2,6f\n"
119 "2: mb\n"
120 ".subsection 2\n"
121 "6: br 1b\n"
122 ".previous"
123 : "=m" (*lock), "=&r" (regx), "=&r" (success)
124 : "m" (*lock) : "memory");
125
126 return success;
127 }
128
arch_write_trylock(arch_rwlock_t * lock)129 static inline int arch_write_trylock(arch_rwlock_t * lock)
130 {
131 long regx;
132 int success;
133
134 __asm__ __volatile__(
135 "1: ldl_l %1,%0\n"
136 " lda %2,0\n"
137 " bne %1,2f\n"
138 " lda %2,1\n"
139 " stl_c %2,%0\n"
140 " beq %2,6f\n"
141 "2: mb\n"
142 ".subsection 2\n"
143 "6: br 1b\n"
144 ".previous"
145 : "=m" (*lock), "=&r" (regx), "=&r" (success)
146 : "m" (*lock) : "memory");
147
148 return success;
149 }
150
arch_read_unlock(arch_rwlock_t * lock)151 static inline void arch_read_unlock(arch_rwlock_t * lock)
152 {
153 long regx;
154 __asm__ __volatile__(
155 " mb\n"
156 "1: ldl_l %1,%0\n"
157 " addl %1,2,%1\n"
158 " stl_c %1,%0\n"
159 " beq %1,6f\n"
160 ".subsection 2\n"
161 "6: br 1b\n"
162 ".previous"
163 : "=m" (*lock), "=&r" (regx)
164 : "m" (*lock) : "memory");
165 }
166
arch_write_unlock(arch_rwlock_t * lock)167 static inline void arch_write_unlock(arch_rwlock_t * lock)
168 {
169 mb();
170 lock->lock = 0;
171 }
172
173 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
174 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
175
176 #endif /* _ALPHA_SPINLOCK_H */
177